I can't stand it when a show/movie ends with ambiguity and the writers say, "we let the viewers decide what happened in their own minds." No you have a story--tell it. All of it.
But that's the thing with art...you want to inspire imagination. You can't do that if you make the totality of the story concrete. That's why the Force in Star Wars was so compelling before the <s>mitochondria</s> midichlorians were introduced.
Though I will agree that there were some things that felt entirely too glossed over in Fury Road...like how Furia or whatever ended up trusting Max way too much on way too little info.